The overall objective of this protocol is to acquire a better understanding of the normal physiological responses of the tongue to contraction tasks. Specifically, our goals are: (1) to quantify 3D volumetric changes of the tongue as a function of maximal voluntary contraction tasks, (2) to examine task-induced changes in blood flow and how tongue vessels and muscles interact during graded lingual contractions, and (3) to determine task-induced variations in the diffusion properties of water molecules in lingual tissue. The protocol was approved on 12/5/2000. Due to a delay in equipment acquisition and optimization, no studies have been conducted to date. The required equipment include the following: Sequoia 512 Ultrasound Imaging System (Acuson, CA), and the Digital Swallowing Workstation (Kay Elemetrics, NJ). The ultrasound system is now operational, and optimization of the Digital Swallowing Workstation is expected to be completed by the manufacturer in two weeks. We, therefore, project that data collection will begin in October, 2001. Despite the delay, we have successfully completed seven Doppler ultrasound pilot studies to refine data collection procedure. In addition, we performed a comprehensive 10-week analysis of the MRI pilot data (six studies) collected from 12/1999 to 8/2000. Preliminary results showed significant tongue volume changes as a function of contraction task. We have quantitative confirmation that our study methods (MRI and ultrasound) are appropriate to address the issues raised in the protocol and will enable us to obtain pioneering information on the functional physiological properties of the in vivo human tongue.